Years after they became the face of political sleaze, Neil and Christine Hamilton remain available for hire. A few days ago, they appeared in Warrington where, the Knutsford Guardian reported: "Christine delighted the audience with stories from the time when they were arrested over false sex allegations." If you were not fully sentient when the Hamiltons first became associated with Hitler impersonations, Skoal Bandits, corruptibility, cash for questions and a massive 1987 freebie at the Ritz, all of which culminated in the 1997 Battle of Knutsford Heath, you might easily believe the couple's principal claim on public attention to be Christine's position as the Face of British Sausage Week 2005.

What with Christine, who has also appeared in pantomime and on I'm a Celebrity, so close to achieving protected, national treasure status, it cannot hurt her reputation to recall a time when, confronted with allegations that he had been suborned by cash and gifts from a lobbyist, her minister husband waved a defiant biscuit at photographers, proposing that – to satisfy the ludicrous puritanism of his accusers – he would declare it on the register of interests. (As it turned out, of course, the itemisation of biscuits was soon to be a feature of many MPs' expenses.)

In the event, having resigned as corporate affairs minister, Hamilton withdrew a £10m libel suit against the Guardian at the last minute after a secretary described seeing Mohamed al Fayed preparing a number of envelopes containing £2,500. The Hamiltons' current notoriety and fortunes are still based effectively on a 1996 Guardian front-page headline: "A liar and a cheat".

Although Hamilton was the most notorious offender, a series of investigations in the 90s revealed a political culture in which, even with a register of interests, numerous MPs were moonlighting as paid lobbyists and consultants. The usual pretext was the supposedly miserable MP's salary. Remove these little freedoms and perquisites, it was argued, and the British could wave goodbye to brilliant, free-thinking mavericks such as Alan Clark, longing to piss on to the public from his departmental balcony, and accept a very different sort of chamber stuffed with squittish, whip-pleasing careerists, some of whom may not even have trained as a barrister. Moreover, didn't intimate relationships with big business, eg the Paris Ritz, help the relevant MPs to remain connected with the real world?

After two decades of intermittent scandals, inquiries and pages of recommendations on appropriate conduct, this conviction that gifted MPs deserve compensation for doing us all a favour still guarantees them a freedom to behave in ways that would look highly eccentric in any other profession and be sackable in most. For instance, in the absence of proved dodginess, Liam Fox's passionate inseparability from his best friend was initially defended by David Cameron as acceptable conduct, and maybe it was, when you think about it, not much more preposterous than his Tory colleague Matthew Offord's determination to have his six-month-old terrier Max with him at work.

When challenged, Offord invoked his right, like Theresa May's cat-loving Bolivian, to a private family life. And Foxy was certainly more frugal, in not personally paying Werritty, than the one in five MPs who, according to the Bureau of Investigative Journalism, still employ close family members to do jobs that, despite being paid by the public, have never been advertised. One MP employed both his estranged wife and his new partner. A ban on nepotism, proposed by the 2009 Committee on Standards in Public Life, was rejected by MPs whose "mental well-being" is, according to the Commons doctor Ira Madan, already compromised by the committee's new expenses system.

In a context where fragile co-workers might need to bring in a pet, or party with the Murdochs, or claim for porn, or conceal obvious conflicts of interest, or taunt disabled people, or go riding with Rebekah Brooks, or throw things, or make discriminatory remarks, or hide from constituents for decades, or claim rent for friends, or employ Andy Coulson, or just get completely rat-arsed and scrap in the corridors, maybe having a Werritty trot meekly after you of a morning was something that could look fairly reasonable.

It must or we would have heard more often the amazed reactions to MPs' weirdness from newbies such as the Totnes MP Sarah Wollaston who, being slow to go native, still finds it startling that legislation should be voted through by MPs who can barely stand. "Who would go to see a surgeon who had just drunk a bottle of wine at lunchtime?" she asked.

The answer, obviously, being an MP who had – courtesy of a lobbyist – just drunk two.

This licence to do as you please, all the greater for MPs enjoying peerless job security in Chelsea, Witney or similar, is reflected in every part of their working lives, from claiming food on expenses to accepting donations from random commercial well-wishers as if the very fact of declaring an obligation in the register of interests is tantamount to its erasure. Thus the education secretary Michael Gove still thinks it no more peculiar to declare a gift of £1,732 worth of clothing from the tailor New & Lingwood than he did, before the Telegraph made something of it, to demand public reimbursement for decorative lamps in the shape of elephants, bought from a shop owned by the mother-in-law of his boss, David Cameron. Perhaps, in fairness, Mr Gove's loss of a lucrative Times column now leaves him no choice between an indefinable debt to a bespoke brand and complete nudity.

More conventionally, Sir Malcolm Rifkind, the MP for Kensington, earns an additional £240,000 from investment groups and others, and Labour's tragic loss David Miliband is similarly only half-way through the revolving door and still fits trips to South Shields around lectures in Abu Dhabi, Sweden, Massachusetts, San Francisco and elsewhere, on top of advising Oxford Analytica and VantagePoint Capital Partners in San Bruno, California (£90,000-£95,000): "I look forward to putting my political experience to work in helping to solve energy innovation and efficiency challenges in today's global financial markets," said the British MP. Glad we could help! It is his former colleague Gordon Brown's peccadillo never to turn up at work at all: an even worse deal, you might think, than Fox's bogof approach.

Reformers who cannot see why modern MPs should not, like normal public sector workers, simply perform their contracted duties without lobbyists' inducements must admit, of course, the real possibility of a talent exodus, in which our indignant apply en masse to VantagePoint Capital Partners, San Bruno, leaving behind an army of professional politicians in the mould of, say Ed Miliband, George Osborne and Ed Balls and those twin hammers of parliamentary sleaze (2009-10) David Cameron and Nick Clegg. The truth is that politics is already a career, although, as Fox demonstrated until the very end, one in which conventional notions of accountability remain as risible as they were in 1994, when Hamilton flourished his ginger biscuit.